Direct involvement of surface IA/E molecules during B cell maturation using an antigen-specific B cell clone.
TP67.14 is a subclone of a resulting B cell hybridoma established by somatic hybridization between splenic B cells of A/J mice immunized with TNP-LPS and 2.52 M, a HAT medium-sensitive mutant of a B cell line; it expresses IgM, B220, IAk, and IEk on the cell membrane and also possesses a receptor molecule for TNP on its surface derived from TNP-reactive B cells of A/J mice used for cell fusion. As shown previously, TP67.14 could be induced to generate a significant amount of anti-TNP antibodies when treated with TNP-conjugated protein such as TNP-BSA and TNP-keyhole limpet hemocyanin without T cell help as well as LPS. Our study was undertaken to investigate direct involvement of surface MHC class II molecules on B cells during B cell maturation by analysis with this Ag-specific B cell clone. The data demonstrate that mAb against IAk and IEk molecules, but not IAd and H-2k, markedly inhibited the differentiative effects of LPS on TP67.14. In contrast, both antibodies specifically augmented the secretion of anti-TNP antibodies by TP67.14 treated with TNP-BSA, although these antibodies alone failed to induce the generation of anti-TNP antibodies. Interestingly, TP67.14 significantly differentiated into anti-TNP antibody secreting cells when incubated with TNP-conjugated monoclonal anti-IAk or anti-IEk antibodies alone; this differentiative effect was much greater than that of TNP-conjugated anti-IAd mAb or purified mouse IgG under the same conditions. Our result suggests that surface IA/E molecules on B cells may be directly involved in a transductional signal for B cell maturation mediated by the cross-linkage of receptor molecules on B cells with Ag.
Hamano
T
T
Second Department of Internal Medicine, Hyogo College of Medicine, Japan.
Iwasaki
T
T
Yamasaki
T
T
Murata
Y
Y
Kakishita
E
E
Nagai
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000921:Antibody-Producing Cells / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D002999:Clone Cells; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D014301:Trinitrobenzenes / Q000276:immunology
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D014301:Trinitrobenzenes